WO2013141620A1

WO2013141620A1 - Secondary coil of receiver for non-contact charging system

Info

Publication number: WO2013141620A1
Application number: PCT/KR2013/002332
Authority: WO
Inventors: 김선섭
Original assignee: Kim Seon Seob
Priority date: 2012-03-23
Filing date: 2013-03-21
Publication date: 2013-09-26
Also published as: JP2015512606A; EP2830191A1; KR101196552B1; US20150054457A1; EP2830191A4; CN104508944A; JP5832693B2

Abstract

A secondary coil (40) applied to an electromagnetic induction type non-contact charging system according to the present invention comprises: a substrate (41); a first coil (42) which is stacked on one side of the substrate (41) and has a first internal space (42a) formed at the center of the first coil; a second coil (43) which is stacked on the other side of the substrate (41) and has a second internal space (43a) formed at the center of the second coil; a first additional pattern (44) electrically connected to the first coil (42); and a second additional pattern (45) electrically connected to the second coil (43), wherein the first internal space (42a) and the second internal space(43a) are not arranged on the same location, are separated at a predetermined distance in the horizontal direction, and are arranged to be offset from each other.

Description

Secondary coil of receiver for contactless charging system

The present invention relates to a contactless charging system, and more particularly, to a battery that is electrically connected to a secondary coil by electromagnetic induction generated between a primary coil of a transmitter and a secondary coil of a receiver adjacent to the transmitter. In a contact charging system, it relates to a secondary coil of a receiver.

As a battery for supplying power to various mobile devices including mobile phones, a multi-use rechargeable battery is widely used instead of a single use. Traditionally, wired (contact) charging has been widely used for charging rechargeable batteries, but the use of contactless (wireless) charging has recently increased.

As a conventional technology related to a contactless charging of a mobile phone, Korean Patent Publication No. 10-1995-0005819 (published on May 31, 1995) discloses a contactless charging system for a wireless telephone, and Korean Patent Publication No. 10-2002- 'Mobile phone wireless charging system' of 0063050 (published Aug. 01, 2002), battery of a mobile communication terminal for wireless charging of Korean Patent Publication No. 10-2004-0019164 (published Mar. 05, 2004) Charger ',' Wireless charging system and method and mobile communication terminal for the mobile communication terminal 'of the Republic of Korea Patent Publication No. 10-2004-0107110 (published Dec. 20, 2004), Republic of Korea Patent Publication No. 10-2007-0033166 (Mobile communication terminal and wireless charging device) of Korean Patent Publication No. 10 (08.07.2007), 'Mobile communication terminal using radio frequency of RFID reader of Korea Patent No. 10-0867405 (registered on October 31, 2008) Battery charger, 'wireless charging' of Korean Utility Model Registration No. 20-0217303 (registered on Jan. 08, 2001) Devices and the like ", the Republic of Korea Registered Utility Model No. 20-0400534 call (2005. 10. 31. Register) of the" cellular phone battery, using wireless radio frequency power into charging power.

The electromagnetic induction charging system, which is a non-contact charging system, has a primary coil installed in a transmitter (charger) supplied with alternating current power, and a secondary coil on the battery side to be charged close to the primary coil and the secondary coil. It is a system that charges a battery by electromagnetic induction generated between coils.

7 is a schematic diagram of a general electromagnetic induction type contactless charging system.

As shown, the electromagnetic induction contactless charging system 100 includes a transmitter 110 and a receiver 120.

The transmitter 110 includes a primary circuit 113 and a transmitter circuit 112 that operates by receiving AC power 111, and the receiver 120 is disposed between the primary coil 113 of the transmitter 110. A secondary coil 121 causing electromagnetic induction and a charging circuit 122 for controlling charging, and the secondary coil 121 is connected to the primary coil while the battery 130 is connected to the charging circuit 122. When approaching the predetermined position of 113, the battery 130 is charged by the induced current induced in the secondary coil 121.

In the example of applying contactless charging to a mobile phone, a typical mobile device, a "charge cover" provided with a receiver (secondary coil and a charging circuit) is manufactured separately from the mobile phone, and the battery of the mobile phone is "charged" using a connector or a cable. The product which charges a battery by putting a "charge cover" in a charger (transmitter) in the state electrically connected to the "cover" has been developed.

However, the "charge cover" method is inconvenient to provide a separate "charge cover" for contactless charging of the mobile phone, the battery cover that is part of the mobile phone (plastic plastic cover to open and close the back of the mobile phone for battery replacement) ), The receiver (secondary coil and charging circuit, in which case the charging circuit is also installed in the body of the mobile phone) by in-mold injection, for example, by contactless charging only by the mobile phone itself without a separate "charge cover" Implementing techniques have been developed.

When contactless charging by electromagnetic induction, when the primary coil and the secondary coil stacked up and down exactly coincide with each other (when the upper and lower overlapping area of the quantum coil is the maximum), the maximum induced electromotive force is generated. As the charging efficiency is achieved, the induction electromotive force gradually decreases as the upper and lower overlapping areas of the quantum coil decrease, and the charging efficiency gradually decreases, and eventually charging stops.

The Wireless Power Consortium (WPC), which provides a standard for contactless charging, suggests some measures to improve the charging efficiency of contactless charging.

The first method of the WPC is a method of accurately maintaining the position of a quantum coil by magnetic force by attaching a permanent magnet in the center of the primary coil and the secondary coil (magnet method).

In the second method, when the receiver (secondary coil) is placed on the transmitter (primary coil), the position of the secondary coil is detected by detecting the position of the secondary coil and moving the primary coil to the position of the secondary coil by a motor. A method of accurately positioning the difference coils (motor control method).

According to the third method, when a plurality of primary coils are provided in the transmitter and the secondary coils of the receiver are raised thereto, current is applied to the primary coil closest to the secondary coil to maintain a large overlapped area of the quantum coils. This method increases the induced electromotive force between the primary coil and the secondary coil (multiple primary coil methods).

However, the "motor control method" and the "plural primary coil method" have a disadvantage in that the product price is relatively increased due to the increase in the number of parts compared to the "magnetic method". In addition, the motor control method has a limitation to limit the weight of the primary coil in order to reduce the load on the motor, the plurality of primary coil method has an excessive increase in the size of the transmitter due to the array structure of the primary coil 1 There is a problem of limiting the size of the secondary coils.

As a result, the motor control method and the plurality of primary coil methods have a reduction in charging efficiency of 10% or more compared with the magnet method, and thus, the magnet method is most widely used.

The magnet method has the advantage of maintaining the up and down positions of the primary coil and the secondary coil in a fixed position at a relatively low cost, but when applied to the mobile phone, the size and weight of the mobile phone increase due to the magnet In addition, the magnet is applied to the magnetic field device (eg, compass, gyro sensor, etc.) built in the cell phone because there is a problem that causes the problem, many products in the actual situation to exclude the magnet design.

Another approach that complements the charging efficiency of contactless charging systems is to apply a PID (Proportional Integral Differential) algorithm for best power transfer control (5.2.3.1 Power transfer in WPC Spec Ver 1.0.3). (see control).

According to the power transmission control method, the charging frequency used for contactless charging is varied in the range of, for example, a maximum of 205 kHz and a minimum of 110 kHz. That is, in the best charging condition with high charging efficiency, where the primary coil and the secondary coil are positioned in place, the charging frequency of 205 kHz or close to it is used. As it is lowered, the low charging frequency of 110 kHz is gradually used, and the current applied to the primary coil is gradually increased to maintain the overall contactless charging efficiency at least above a certain efficiency.

However, even if the charging frequency is varied according to the power transmission control method, for example, in the range of 205 kHz to 110 kHz to improve the charging efficiency, even if the induced electromotive force is generated, the primary coil and the secondary coil may be out of position. For example, in the outermost position where the minimum induced electromotive force is induced, the charging efficiency is lowered by more than 20% compared to the maximum charging efficiency.

In addition, in the outermost position where the charging efficiency is low, the rectifier circuit of the secondary coil requests a higher voltage increase in the primary coil to compensate for the shortage of the charging voltage due to the decrease in induced electromotive force. As the amount of the secondary coil deviates from the primary coil, only one side of the secondary coil flows into the current, and the current increases, eventually causing heat generation during wireless charging.

As a conventional technology for improving the charging efficiency of the contactless charging system, 'wireless charging system and method' of Republic of Korea Patent Publication No. 10-2010-0074595 (published on July 02, 2010), Republic of Korea Patent Registration 10-1063154 'Contactless charging device' of Korean Patent No. (2011. 09. 01. registered), 'Wireless charger with improved variation of charging efficiency' of Korean Patent No. 10-0819604 (registered March 28, 2008), Republic of Korea Patent No. 10-2009-0025876 (published on March 11, 2009) 'Position-aware contactless power supply and battery charging device and charging system using the same', Republic of Korea Patent Publication No. 10-2009-0059507 (2009. 'Contactless charging device with charging status display function and charging method' of 06. 11.), 'wireless charging menu provision function of Korea Patent Publication No. 10-2009-0062224 (2009. 06. 17. Publication) And a charging method thereof.

An object of the present invention is to improve the charging efficiency of a contactless charging system.

An object of the present invention relates to a contactless charging system that charges a battery by electromagnetic induction between a primary coil of a transmitter and a secondary coil of a receiver, wherein the charging is caused by deviation of the secondary coil relative to the primary coil. It is an object of the present invention to provide a receiver secondary coil and a contactless charging system employing the same, which can alleviate a decrease in efficiency.

According to the present invention, there is provided a secondary coil of a receiver, which is applied to a contactless charging system for charging a battery electrically connected to the primary coil of the transmitter by an electromagnetic induction generated between the primary coil and the primary coil.

The secondary coil of the receiver according to the present invention includes a base surface, a first coil, a second coil, a first additional pattern, and a second additional pattern.

The base surface forms a support surface.

The first coil is laminated and attached to one side of the substrate, and is formed by winding a plurality of times outward in one direction with a first internal space at the center.

The second coil is laminated and attached to the other side of the substrate, is formed by winding a plurality of times outward in the same direction as the first coil with a second internal space in the center, and is electrically connected to the first coil. have.

The first additional pattern is formed on the other side of the base surface of the non-overlapping portion of the first coil that does not overlap the second coil, and is electrically connected to the first coil on one side.

The second additional pattern is formed on one side of the base surface of the non-overlapping portion of the second coil that does not overlap with the first coil, and is electrically connected to the second coil on the other side.

The first inner space of the first coil and the second inner space of the second coil are not disposed at the same position but are “spread out” to a position shifted by a predetermined distance in the horizontal direction.

The diffusion arrangement of the first coil and the second coil exceeds a 0% diffusion arrangement in which the centers of the first internal space and the second internal space coincide with each other, and the second coil has a diameter of the first internal space. It can be set to the range below 100% diffusion arrangement | deviation shifted | deviated to the horizontal direction from the said 1st coil by this much.

Regarding the contactless charging system for charging a battery by electromagnetic induction between the primary coil of the transmitter and the secondary coil of the receiver, by applying a coil having a diffusion arrangement structure as the secondary coil of the receiver, There is an effect that can alleviate the decrease in the charging efficiency caused by the deviation of the secondary coil in position.

1 is a schematic diagram of an exemplary contactless charging system to which the present invention is applied;

2 is an exploded perspective view of an exemplary secondary coil in accordance with the present invention;

3 is a front view (A) and back view (B) of an exemplary secondary coil in accordance with the present invention;

4 is a plan view and a cross-sectional view of an exemplary secondary coil A and a control example secondary coil B according to the present invention;

5 is a plan view of an exemplary secondary coil in accordance with the present invention with 50% (A) and 100% (B) diffusion arrangements;

6 is a layout diagram of the positional change of the secondary coil A and the comparative secondary coil B of the present invention with respect to the primary coil for measuring the change in the input current (charging efficiency);

7 is a schematic diagram of a contactless charging system of a general induction current method.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. The following specific examples merely illustrate the invention and do not limit the scope of the invention.

As shown in FIG. 1, the contactless charging system 1 to which the secondary coil 40 of the present invention is applied is similarly to a contactless charging system applied to a mobile phone, which is a typical portable device 2, and the like. And a transmitter 10 (eg, a charging mat) provided with the secondary coil 20 and a receiver 30 (eg, a mobile phone) provided with the secondary coil 40. Hereinafter, the mobile device 2 will mainly be described as an example of the mobile device 2, and the same reference numeral 2 is used for the mobile device and the mobile phone.

As is known, in addition to the primary coil 20 and the secondary coil 40, the transmitter 10 and the receiver 30 are provided with circuits and ferrites necessary for charging, but such circuits are directly related to the present invention. Therefore, illustration or description thereof will be omitted.

The contactless charging system 1 to which the present invention is applied has a primary coil (when the secondary coil 40 of the receiver 30 is placed close to the primary coil 20 of the transmitter 10, as in the related art. By the electromagnetic induction generated between the 20 and the secondary coil 40, the battery 50 is electrically connected to the secondary coil 40.

In the secondary coil 40 according to the present invention, the coils wired in a loop pattern are not wired on a single surface, but as shown in FIGS. 2 to 5, the base surface 41 is centered on a flat base surface 41. The first coil 42 is stacked on one side (eg, the rear surface) of the substrate, and the second coil 43 is stacked on the other side (eg, the surface) of the base surface 41.

The base surface 41 is a layer to which the first coil 42 and the second coil 43 are attached and supported. For example, FPCB such as a thin film or a double-sided adhesive film may be applied. .

The first coils 42 stacked on one side of the base surface 41 are coils of a loop pattern which are wound (wound) a plurality of times outward in one direction with the first internal space 42a at the center thereof. The second coil 43 stacked on the other side of the base surface 41 is also a coil of a loop pattern wound many times outward in the same direction as the first coil 42 with the second internal space 43a at the center thereof. .

When the winding direction is reversed, the magnitude of the magnetic field generated by the first coil 42 and the second coil 43 is canceled, so that the first coil 42 and the second coil 43 are wound in the same direction.

The first coil 42 and the second coil 43 are electrically connected to the respective inner ends through the via holes H1 to become one secondary coil 40 as a whole, and the first coil 42 and the second coil 43. Each outer end of the coil 43 forms

terminal connecting portions

42b and 43b for connecting to the charging circuit side.

According to the feature of the present invention, the first coil 42 and the second coil 43, as shown in Fig. 4B, the first inner space 42a and the second inner space 43a exactly matches up and down As shown in FIG. 4A and the like, the first internal space 42a and the second internal space 43a are stacked in a state where they are shifted apart by a predetermined distance in the horizontal direction.

In the secondary coil 40 of the present invention, the first internal space 42a of the first coil 42 and the second internal space 43a of the second coil 43 are not stacked up and down to be spaced apart from each other by a predetermined distance. The state in which they are shifted to the position is called "diffusion arrangement".

For example, an arrangement in which the centers of the first inner space 42a and the second inner space 43a are exactly coincident (an arrangement in which the first coil and the second coil are exactly aligned up and down) is referred to as "0% diffusion arrangement". According to the present invention, when the arrangement in which the second coil 43 deviates horizontally from the first coil 42 by the diameter R of the first internal space 42a is referred to as "100% diffusion arrangement", The range of the diffusion arrangement | positioning of the 2nd coil 43 with respect to the 1st coil 42 in the secondary coil 40 can be made into the range of "0% <diffusion arrangement of a 2nd coil <= 100%". At this time, when the first inner space 42a and the second inner space 43a are not circular but rectangular, the diameter R is the length of the shorter side of the rectangle.

FIG. 5A shows "50% diffusion arrangement" in which the second coil 43 is displaced from the first coil 42 by the radius R / 2 of the first inner space 42a, and B of FIG. 1 shows "100% diffusion arrangement" in which the second coil 43 is displaced from the first coil 42 by the diameter R of the inner space 42a. 4B shows a " 0% diffusion arrangement " in which the first inner space of the primary coil 42 and the second inner space of the secondary coil 43 completely coincide.

In the secondary coil 40 of the present invention, the first coil 42 on one side of the base surface 41 and the second coil 43 on the other side of the base surface 41 are not disposed to be vertically aligned with each other. Since the first coil 42 and the second coil 43 intersect with the base surface 41 between the upper and lower portions of the first coil 42 and the second coil 43 because they are arranged in a position shifted horizontally out of a predetermined distance, It becomes a structure.

That is, the overlapping portion is a portion where all of the first coil 42, the base surface 41, and the second coil 43 exist up and down, and the non-overlapping portion includes only the base surface 41 and the first coil 42, or Only the base surface 41 and the second coil 43 are present.

As shown in FIG. 4A and the like, the secondary coil 40 according to the present invention includes the first coil 42 and the non-overlapped portion of the first coil 42 not overlapping the second coil 43. The first additional patterns 44 electrically connected are stacked on the other side of the substrate 41. Similarly, the second additional pattern 45 electrically connected to the second coil 43 is connected to one side of the substrate 41 at the non-overlapped portion of the second coil 43 not overlapping the first coil 42. Lamination is formed.

Preferably, the first additional pattern 44 is formed over the widest area as long as it is not shorted with the second coil 43, and likewise, the second additional pattern 45 is also not shorted with the first coil 42. Form as wide as possible in the range.

As shown in FIG. 3, the circular first coils 42 and the circular second coils 43 are diffused to a position shifted out of a horizontal distance by a predetermined distance, and at least some of the

internal spaces

42a and 43a are disposed. When the diffusion arrangement is performed by a distance overlapping each other, the relatively large arc-shaped first additional pattern 44a and the second internal portion existing outside the second internal space 43a are formed in the non-overlapped portion of the first coil 42. A relatively small arc-shaped first additional pattern 44b existing in the space 43a may be formed.

Similarly, the non-overlapping portion of the second coil 43 also exists inside the relatively large arc-shaped second additional pattern 45a and the first inner space 42a that exist outside the first inner space 42a. A relatively small arc-shaped second additional pattern 45b may be formed.

At this time, preferably, the first additional pattern 44 is wired in the same pattern as the first coil 42 of the corresponding portion existing on the opposite side of the substrate 41, and the second additional pattern 45 is the substrate 41. Wiring is carried out in the same pattern as the second coil 43 of the corresponding part existing on the opposite side.

The secondary coil 40 according to the present invention is, for example, 0.0175 mm (0.5 ounces) to 0.105 mm (3 ounces) on both the upper and lower sides of a base thin film such as a polyimide film as a substrate 41 having a thickness of 0.025 mm or less. It can be produced by etching a conductive thin film coated with a conductive thin film such as copper foil (or copper plating) having a thickness.

That is, the conductive thin films on both the upper and lower sides of the conductive thin film are etched according to the pattern of the first coil 42 and the second coil 43 of the desired secondary coil 40, and the first coil 42 and the second coil are etched. The via hole H1 may be formed at a position corresponding to the inner end of the coil 43, and soldered through the via hole to electrically connect the inner end.

Formation of the first additional pattern 44 and the second additional pattern 45 may etch the double-sided conductive thin film of the conductive thin film to form the first coil 42 and the second coil 43 on both sides of the substrate 41. When each of them is formed, the first additional pattern 44 and the second additional pattern 45 are also formed by etching, and then soldered through the via holes H2 to form respective substrates of the first additional pattern 44. Electrically connecting the corresponding respective wires of the first coil 42 on the opposite side to 41 and similarly connecting the respective wires of the second additional pattern 45 to the second coil on the opposite side of the substrate 41. It can be formed by electrically connecting to the respective respective wirings of (43).

The first additional pattern 44 and the second additional pattern 45 are removed by corrosion when etching the double-sided conductive thin film of the double-sided conductive thin film to form the first coil 42 and the second coil 43. Since it is formed in the conductive thin film of the part, it can be formed without additional input of the material.

In the secondary coil 40 according to the present invention, the first additional pattern 44 and the second additional pattern 45 are not limited to the maximum thickness of the secondary coil 40 while being limitedly applied only to the non-overlapping portions. While supplementing by partially increasing the thickness of the first coil 42 and the second coil 43, the overall resistance of the secondary coil 40 is reduced, resulting in improved charging efficiency and reduced heat generation. Become useful.

The inventor applies the 50% diffusion arrangement and the 100% diffusion arrangement to manufacture the secondary coil 40 according to the present invention, while all other conditions are the same while the first coil and the second coil are exactly matched to 0%. The secondary coils (control example, B of FIG. 4) to which the diffusion arrangement was applied were produced, respectively, and the secondary coils 40 and the secondary coils of the comparative example of the present invention thus prepared were the primary coils 20 having the same characteristics. On the same condition as above, the input current value consumed by the transmitter of the primary coil 20 was measured while setting the charging current of the battery 50 to 600 mA.

At this time, the position of the secondary coil 40 mounted on the primary coil 20 is as shown in Figure 6, where A of Figure 6 is a view to which the secondary coil 40 of the present invention is applied. 6B is a diagram to which a secondary coil of a control example is applied. In Fig. 6, A1 and B1 are the state in which the secondary coil 43 is correctly positioned on the primary coil 42 (the preferred state with the highest charging efficiency), and A2 and B2, A3 and B3, A4 and B4 and A5 and B5 is a state where the secondary coil 43 is shifted 10 mm from the primary coil 42 to the right side, the upper side, the left side and the lower side, respectively (the state where the charging efficiency is lower than the best).

6 positions of the secondary coil (FIG. 6A) of the present invention with 50% diffusion arrangement and 100% diffusion arrangement and the secondary coil (B of FIG. 6) of the comparative example with 0% diffusion arrangement. The measured values of the input current at the transmitter including the primary coils 42 measured at Table 1 are shown in Table 1.

Table 1

50% diffusion (invention)		100% diffusion (invention)		0% Diffusion (Control)
location	Input current (mA)	location	Input current (mA)	location	Input current (mA)
A1	220	A1	220	B1	220
A2	256	A2	250	B2	260
A3	255	A3	250	B3	260
A4	255	A4	250	B4	260
A5	255	A5	250	B5	260

As can be seen from Table 1, in the most preferable case (A1, B1) in which the secondary coil 40 is correctly positioned in the primary coil 20, the input current on the primary coil side in both the present invention and the comparative example. As 220 mA, the lowest value showing the maximum charging efficiency was measured, and there was no difference between the present invention and the control example.

In the case where a decrease in the charging efficiency in which the secondary coils 40 are shifted out of the horizontal direction by a distance of 10 mm from the primary coils 20 is anticipated (A2 to A5 and B2 to B5), contrast of 0% diffusion arrangement For example, while the input current is 260 mA, the input current when the secondary coil 40 according to the present invention is applied was measured at 256 mA and 255 mA for the 50% diffusion arrangement and 250 mA for the 100% diffusion arrangement.

As a result, when comparing the secondary coil 40 of the present invention and the secondary coil of the control example, the charging efficiency is the same when the secondary coil is placed on the primary coil, but the secondary coil is the primary When the charging efficiency decreases when the coil is out of position, the reduction of the charging efficiency of the secondary coil of the present invention is reduced compared to the secondary coil of the comparative example (the input current used to obtain the same charging current of 600 mA is relatively Low).

That is, it can be seen that the application of the secondary coil of the present invention significantly alleviates the decrease in the charging efficiency caused when the secondary coil is charged in a state away from the position of the primary coil. In addition, it can be seen that the mitigation effect of such decrease in charging efficiency is greater as the degree of diffusion increases to at least 100%.

In addition, the present inventors additionally measured the input current on the primary coil side even for a structure in which the degree of diffusion is greater than 100%. When the secondary coil is out of position of the primary coil, 100% To a certain extent exceeding, the effect of mitigating the charging efficiency decrease was lower than that of the 100% diffusion batch, but it was more effective than the 0% diffusion batch of the control, but in the case of in-situ, the diffusion batch exceeded 100%. In the case of, the charging efficiency was lower than in all cases of the diffusion batch below 100%.

In addition, since the diffusion arrangement exceeds 100%, the work of electrically connecting the inner ends of the first coil 42 and the second coil 43 becomes difficult and the area occupied by the secondary coil is excessively increased. The diffusion batch preferably does not exceed 100%.

The effect on the charging efficiency according to the diffusion arrangement of the secondary coil 40 is considered to be achieved by reducing the magnetic field loss of the induced electromotive force induced between the primary coil and the secondary coil.

The secondary coil 40 of the present invention used for the measurement was produced by etching a conductive thin film of double-sided 2 ounce copper foil, the inductance was 10uH, the outer diameter of the first coil 42 and the second coil 43 ( R1) is 43mm ± 10mm, inner diameter (R2) is 27mm, the loop number of the loop pattern of the first coil 42 and the second coil 43 is 16 times in total 8 times, the loop width of each rotation is 1mm, The spacing between loops was 0.15 mm each.

The thickness of the copper foil applied to the secondary coil can be in the range of 1 to 3 ounces, and the change in the coil inductance value due to the thickness difference can be neglected, but the resistance value decreases when using the 2 ounce copper foil rather than the 1 ounce copper foil. do. In the case of the secondary coil used for the measurement, the resistance value was approximately 800 mΩ for the 1-ounce copper foil, 500 mΩ or less for the 2-ounce copper foil, and 300 mΩ for the 3-ounce copper foil.

As described above, since the change in inductance according to the change of the thickness of the copper foil in the secondary coil is small, the resistance value is significant, so it is necessary to increase the thickness of the copper foil in order to reduce the resistance value.

However, increasing the thickness of the copper foil by 3 ounces or more to reduce the resistance of the secondary coil should be repeated two or three times to improve the accuracy. Increasing the loop width of the pattern at the same thickness of copper foil can reduce the resistance value. However, increasing the loop width requires insufficient rotation speed of the loop to match the inductance value. There is a burden of cost increase.

In the case of the secondary coil 40 according to the present invention used for the above measurement, the reduction of the resistance value due to the addition of the first additional pattern 44 and the second additional pattern 45 is achieved by 0% diffusion without the additional pattern. In comparison, it was about 20% for 50% diffusion and about 40% for 100% diffusion. In this case, in the case of the secondary coil in which the diffusion arrangement of 50% or 100% is applied but the first additional pattern 44 and the second additional pattern 45 are not applied, the resistance value is substantially the same as that of 0% diffusion.

Therefore, the secondary coil 40 according to the present invention is very effective in reducing the resistance value without increasing the thickness of the copper foil or applying the multilayer structure by using the copper foil to be lost by etching as the

additional patterns

44 and 45. .

Since the total power consumed for charging in the charging circuit of the receiver is supplied through the secondary coil of the receiver, inductance and resistance of the secondary coil of the receiver are important. If the current flowing through the secondary coil is the same, the higher the resistance of the secondary coil, the higher the power consumed, so that a relatively high heat generation occurs, and the lower the resistance, the lower the power consumed at the same current, the lower the heat generation. For example, changing the copper foil of the secondary coil from 1 ounce to 2 ounces when charging to 600 mA at the receiver can lower the heat generation temperature of the secondary coil by approximately 3 degrees, and by changing it to 3 ounces an additional approximately 3 degrees. Can be lowered. In the secondary coil 40 according to the present invention used for the measurement, by applying the first additional pattern 44 and the second additional pattern 45, the heating temperature can be lowered by approximately 1 degree each time the resistance value is lowered by 100 mΩ.

When the diffusion arrangement is applied to the secondary coil 40 as in the present invention, the change in the overlapping area of the primary coil and the secondary coil becomes relatively low when the receiver moves on the transmitter, thereby reducing the magnetic field induced in the secondary coil. Since there is little variation, when the above-mentioned charging frequency is changed to compensate for charging efficiency, there is also an effect that the amount of change in the charging frequency is stabilized.

In the above, the case where the secondary coil 40 is formed in the structure of the diffusion arrangement has been described as the present invention, and when the same diffusion arrangement as in the secondary coil of the present invention is applied to the primary coil 20, the primary It is expected that charging efficiency will be improved even if diffusion arrangement is applied to both coil and secondary coil.

In addition, although the secondary coil 40 of the illustrated embodiment illustrated the case of the most common form of a circular loop, it is not particularly limited to form in the shape of another loop pattern, such as a square rather than a circle.

Claims

Receiving unit applied to a contactless charging system for charging the battery 50 electrically connected to the primary coil 20 of the transmitter 10 by electromagnetic induction generated between the primary coil 20 ( In the secondary coil 40 of 30),

A base surface 41 forming a support surface;

A first coil 42 attached to one side of the base surface 41 and formed by winding a plurality of times outwardly in one direction with a first internal space 42a at the center thereof;

Stacked and attached to the other side of the base surface 41, the second inner space (43a) in the center is formed by winding a number of times outward in the same direction as the first coil 42, the first coil 42 A second coil 43 electrically connected to the second coil 43;

First to be formed on the other side of the base surface 41 of the non-overlapping portion of the first coil 42 that does not overlap the second coil 43, and electrically connected to the first coil 42 on one side An additional pattern 44; And

A second formed on one side of the base surface 41 of the non-overlapping portion of the second coil 43 not overlapping with the first coil 42 and electrically connected to the second coil 43 on the other side An additional pattern 45; Including:

The first inner space 42a of the first coil 42 and the second inner space 43a of the second coil 43 are not disposed at the same position but diffuse to a position shifted by a predetermined distance in a horizontal direction. The secondary coil of the receiver for a contactless charging system, which is arranged.
The method of claim 1,

The diffusion arrangement of the first coil 42 and the second coil 43 exceeds a 0% diffusion arrangement in which the centers of the first internal space 42a and the second internal space 43a coincide with each other. The second coil 43 is diffusely arranged in a range of less than or equal to 100% diffusion arrangement shifted out of the horizontal direction from the first coil 42 by the diameter R of the first internal space 42a. Secondary coil of the receiver for contactless charging system.